Maybe not that much, depending on where you are and how "proactive" you've already been before now.

Seriously, I don't think Friday's Supreme Court decision in Obergefell v. Hodges will be that big a deal for most employers. The Supreme Court already decided in 2013 that the federal definition of "spouse" included same-sex spouses (assuming the marriage was legally valid where entered). The U.S. Department of Labor issued regulations earlier this year taking the same position with respect to the definition of "spouse" in the Family and Medical Leave Act.

(That FMLA rule was enjoined by a federal judge in Texas, but the Obergefell decision would allow the DOL rule to go into effect.)

Even in states that did not recognize same-sex unions, many employers were recognizing them as a matter of policy.

If you haven't done so, you'll want to ensure that your benefits plans (health, life insurance, etc.) define “spouse” in accordance with the Court’s ruling. But even if you don't, your benefits providers are probably all over it.

You may also want to develop a strategy for dealing with "sensitivity" and harassment issues among your employees, if you haven't already been covering sexual orientation, gender identity, and related issues in your training. Employees should understand that they are to treat each other with courtesy and respect, and to avoid harassing or discriminatory behavior on any basis. On the other hand, you shouldn't go so far as to require employees to "affirm" a particular mode of living. Some employees may object based on sincerely held religious beliefs, which are also legally protected, as Justice Kennedy made clear in his majority opinion.

Really, pretty easy, huh?